The present invention relates to steering wheels for automotive vehicles comprising a steering wheel hub consisting of a light metal die casting and a steering wheel gear rim connected by means of spokes with the steering wheel hub. The invention also concerns the process for the manufacture of steering wheels.
In known steering wheels the inserts of the steering wheel spokes consist of steel shaped parts joined with the steering wheel hub into a skeleton body. To connect the respective parts, a cast joint must be provided from the spoke inserts to the hub and a welded joint is provided from the spoke inserts to the steering wheel rim. Another welded joint at the driving surface of the rim which is bent from a rod shape into an annulus is also provided. Because of this construction, the manufacture of the steering wheel skeletons requires a significant number of welding operations, the number depending on the number of steering wheel spokes. For production technological reasons the superposition of two welded joints must be avoided.
Another disadvantage of known steering wheels consists of the fact that they frequently are of an undesirable total weight. This detrimentally affects the steering behaviour of the vehicle. Because of the great mass particularly in the rim area remote from the hub and the resulting high kinetic energy, there is often a deflection of the steering wheel past its center position in the opposite direction during the automatic return of the steering wheel after steering deflections. Under certain conditions, this may lead to the straying of the vehicle from its intended direction of travel. Therefore, there has long been a need for a steering wheel satisfying all mechanical and safety requirements, that is, light in weight and that consists particularly in its rim of a hollow shape. One of the problems of the manufacture of such a steering wheel has always been the difficulty of providing a strong and safe welded joint between the solid spokes and the hollow configurations of the rim.